A corydoras entry starts at the substrate
A water change in a corydoras tank is really two jobs — replacing water and vacuuming the floor the fish live on — so the log records both. Write down the amount changed, how thoroughly the substrate was cleaned and, in plain words, how much waste it gave up. Follow with temperature, ammonia, nitrite and nitrate. Corydoras breathe and feed at the bottom, where uneaten food and waste settle, so a tank can test acceptably at the surface while the fish's own layer tells a poorer story. The vacuuming note is what connects the readings to the fish's reality.
Barbels and behaviour, logged like readings
A corydoras's barbels — the whiskers it tastes the substrate with — are a health instrument you can read at a glance, so describe them at each change: full and even, or looking worn. Pair that with behaviour: a contented group shuffles around the glass in the evening, rests together in a favourite corner and darts to the surface occasionally for air. A group gone still, or one fish separating itself, deserves an entry of its own. When barbel notes and behaviour notes sit beside the water readings, you can see whether a decline followed a missed vacuuming, a new sharp-edged décor item or a swing in temperature.
Oxygen and flow deserve a line of their own
Corydoras appreciate well-oxygenated water and are quick to show it when the bottom layer goes stale. Note the things that affect it: the air stone cleaned or replaced, the filter outlet adjusted, surface film appearing or clearing. If the group starts gathering near the filter outflow or making repeated trips to the surface, the log lets you check what changed in flow or cleaning before assuming the worst. These are small observations, but in a bottom-dweller's tank they are the difference between guessing and knowing.
Writing the entry so the next keeper understands it
Tanks with corydoras are often community tanks with several helpers, and a log written in one person's private shorthand fails the moment someone else picks up the siphon. Use whole words for the fish — the bronze group, the pandas — and describe locations plainly: left corner under the wood, not 'the usual spot'. Record new arrivals and any fish moved out, since corydoras groups change and stocking drives the waste load. A log a substitute keeper can follow without a phone call is the real test of the system.
Splitting the bottom-of-tank chores fairly
Vacuuming, water carrying and testing are separate jobs that suit separate hands, which makes a corydoras tank a natural shared routine. KinsLe's Care Teams lets you assign those duties per pet to the family members who help, and each completed task is marked with a timestamp — so one person can see the substrate was vacuumed and tested this week, and nobody repeats a change the fish did not need.